{"answers":{"affected":"6 open source packages ship an affected version, including github.com/free5gc/ausf and github.com/free5gc/free5gc.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53551 exists.","fix":"Upgrade github.com/free5gc/ausf to 1.4.5 or later.","what":"CVE-2026-53551 is a medium-severity denial of service vulnerability in free5gc ausf, published on 31 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-53551 and fix it if it is affected.\n\nWhat it is: CVE-2026-53551 is a medium-severity denial of service vulnerability in free5gc ausf, published on 31 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53551 exists.\n\nAffected packages and fixed versions:\n- github.com/free5gc/ausf (Go): affected all versions; fixed in 1.4.5\n- github.com/free5gc/ausf (Go): affected all versions; fixed in 1.4.5\n- github.com/free5gc/ausf (Go): affected all versions; fixed in 1.4.5\n- github.com/free5gc/free5gc (Go): affected all versions; fixed in 4.2.2\n- github.com/free5gc/free5gc (Go): affected all versions; fixed in 4.2.2\n- github.com/free5gc/free5gc (Go): affected all versions; fixed in 4.2.2+incompatible\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-53551/ (Markdown: https://insights.sbomify.com/CVE-2026-53551/index.md)","id":"CVE-2026-53551","markdown":"https://insights.sbomify.com/CVE-2026-53551/index.md","name":"CVE-2026-53551","record":{"aliases":["GHSA-qj55-47fp-p62j","GO-2026-6161"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service","data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"5G core network","requires_auth":"none","summary":"An unauthenticated attacker can cause denial of service and leak stack traces by sending null bytes in authentication requests to the free5GC AUSF.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-20","name":"Improper Input Validation"}],"description":"free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the free5GC AUSF (Authentication Server Function) does not validate the supiOrSuci field in UE authentication requests. Null bytes (\\x00) and other control characters pass through JSON parsing unchanged and are forwarded to the UDM in an unescaped URL path. This causes Go's net/url.Parse() to fail, returning HTTP 500 \"System failure\" and leaking internal stack traces. An unauthenticated attacker can trigger this at scale causing denial of service for all subscribers attempting authentication through the affected AUSF. This vulnerability is fixed in 1.4.5.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"free5GC AUSF: null byte injection in supiOrSuci causes HTTP 500 internal service failure","id":"CVE-2026-53551","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":6,"n_references":6,"next":{"headline":"Goploy: Cross-namespace IDOR and RCE via body-supplied row id in project and project_file handlers","id":"CVE-2026-53552"},"packages":[{"ecosystem":"Go","fixed":["1.4.5"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/ausf","purl":null,"source":"GHSA-qj55-47fp-p62j"},{"ecosystem":"Go","fixed":["1.4.5"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/ausf","purl":"pkg:golang/github.com/free5gc/ausf","source":"GHSA-qj55-47fp-p62j"},{"ecosystem":"Go","fixed":["1.4.5"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/ausf","purl":"pkg:golang/github.com/free5gc/ausf","source":"GO-2026-6161"},{"ecosystem":"Go","fixed":["4.2.2"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/free5gc","purl":null,"source":"GHSA-qj55-47fp-p62j"},{"ecosystem":"Go","fixed":["4.2.2"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/free5gc","purl":"pkg:golang/github.com/free5gc/free5gc","source":"GHSA-qj55-47fp-p62j"},{"ecosystem":"Go","fixed":["4.2.2+incompatible"],"introduced":["0"],"last_affected":[],"package":"github.com/free5gc/free5gc","purl":"pkg:golang/github.com/free5gc/free5gc","source":"GO-2026-6161"}],"prev":{"headline":"js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases","id":"CVE-2026-53550"},"products":["ausf","free5gc"],"published":"2026-07-31","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-03","vendors":["free5gc"]},"summary":"An unauthenticated attacker can cause denial of service and leak stack traces by sending null bytes in authentication requests to the free5GC AUSF.","url":"https://insights.sbomify.com/CVE-2026-53551/"}